THE ASH OF PLANTS. 187 



minute traces of sodium when mixed with much potassi- 

 um ; while, on the other hand, sodium, if present to the 

 extent of a per cent or more, is very liable to be estimated 

 too high. It has therefore been doubted if these high 

 percentages in the ash of grains are correct. 



Again, the processes formerly employed for preparing 

 the ash of plants for analysis were such as, by too elevated 

 and prolonged heating, might easily occasion a partial 

 or total expulsion of sodium from a material which prop- 

 erly should contain it, and we may hence be in doubt 

 whether the older analyses, in which sodium is not men- 

 tioned, are to be altogether depended upon. 



The later analyses, especially those by Bibra, Zoeller, 

 Arendt, Bretsclmeider, Ritthausen, and others, who have 

 employed well-selected and carefully-cleaned materials for 

 their investigations, and who have been aware of all the 

 various sources of error incident to such analyses, must 

 therefore be appealed to in this discussion. From these 

 recent analyses we are led to precisely the same conclu- 

 sions as were warranted by the older investigations. Here 

 follows a statement of the range of percentages of sodium 

 oxide in the ash of several field crops, according to the 

 newest analyses: 



SODIUM OXIDE (SODA) IN LATER ASH-ANALYSES. 



Ash of Wheat kernel, none, Bibra, to 5% Bibra. 



0.28% Lawes& Gilbert," 1.18% 



Potato tuber, none, j ^etoforff, " 4 % Wolff " 



Barlev kernel I l % Blbra < ROIL { Bibra. 



ielf \ 2% Zoeller, b %{veltmann. 



" " " 7% Zoeller. 



s*.,!r-ir hPot J 4 % Ritthausen, " 29.8% Ritthausen. 



) 7% Bretsclmeider, " 16.6% Bretsehneider. 



Turnip root, 7.7% Anderson, " 17.1% Anderson. 



Although, as just indicated, sodium in some instances 

 Las been found wanting in the wheat kernel and in po- 

 tato tubers, it is not certain that it was absent from other 

 parts of the same plants, nor has it been proved that 

 sodium is wanting in any entire plant which has grown 

 on a natural soil. 



